Trapiche emeralds are unknown to most people, and surprisingly, to many jewelers as well. The black-spoked wheel formation occurs naturally and makes for a very interesting conversation piece. As is typical in trapiches, the black lines go all the way through the green emerald material and completely around it. Some formations are better than others and this particular stone has relatively good, clean lines, but it is an extremely dark stone and appears even black sometimes. Most trapiches we sell go to collectors or creative customers looking for something out of the ordinary.